Troubleshooting guide

1-3
Cisco Wide Area Application Services Configuration Guide
OL-26579-01
Chapter 1 Configuring File Services
Overview of File Services Features
Overview of File Services Features
This section provides an overview of the WAAS file services features and contains the following topics:
• Automatic Discovery, page 1-3
• Data Coherency, page 1-3
• Data Concurrency, page 1-5
• Prepositioning, page 1-5
• Microsoft Interoperability, page 1-6
To accelerate CIFS traffic, you can use one of the following two accelerators:
• CIFS—The CIFS accelerator was introduced in WAAS version 4.1.1, relies on automatic discovery,
transparently accelerates CIFS traffic, supports prepositioning of files, and requires no
configuration. This accelerator also supports the Windows Print accelerator, which accelerates print
traffic between clients and a Windows print server. The CIFS accelerator is enabled by default.
Supports the SMB 1.0 protocol for CIFS traffic.
• SMB—The SMB accelerator, introduced in WAAS version 5.0.1, relies on automatic discovery,
transparently accelerates CIFS traffic, and does not support prepositioning or the Windows Print
accelerator. This accelerator has configuration options that you can fine-tune for specific needs.
Supports the SMB 1.0, 2.0, and 2.1 protocols for CIFS traffic and signed SMB traffic.
The CIFS and SMB accelerators are not compatible and only one can be enabled on a WAE. Enabling
one automatically disables the other.
Peer WAEs must both use the same accelerator (CIFS or SMB) because the two different accelerators do
not interoperate. They can coexist in the same WAAS network, but only on separate devices that are not
peers.
Note Legacy mode WAFS is no longer supported beginning with WAAS version 4.4.1. Legacy WAFS users
must migrate to the CIFS or SMB accelerator before upgrading.
Automatic Discovery
The automatic discovery feature allows you to enable CIFS without having to register individual file
servers in the WAAS Central Manager. With the automatic discovery feature, WAAS attempts to
automatically discover and connect to a new file server when a CIFS request is received.
Data Coherency
WAAS software ensures data integrity across the system by using two interrelated features – coherency,
which manages the freshness of the data, and concurrency, which controls the access to the data by
multiple clients.
Maintaining multiple copies of data files in multiple locations increases the likelihood that one or more
of these copies will be changed, causing it to lose consistency or coherency with the others. Coherency
semantics are used to provide guarantees of freshness (whether the copy is up-to-date or not) and the
propagation of updates to and from the origin file server.
The WAAS software applies the following coherency semantics to its built-in coherency policies: